1. Field of the Invention
The present invention relates to a method of judging whether or not a protein has thermostability by focusing on a protein produced by an organism, and calculating a characteristic value related to thermostability from the data of the amino acid sequence or the nucleotide sequence of the protein. More particularly, the invention relates to a method of judging the thermostability of a protein, which judges whether or not a test protein has thermostability, comprising the steps of calculating an analytical value specific to the test protein by a principal component analysis based on the amino acid composition of the protein, and comparing the analytical value with an analytical value of a protein which is retained by a thermostable organism and corresponds to the test protein.
In addition, the invention relates to a program for judging whether or not the protein has thermostability by focusing on a protein produced by an organism, and calculating a characteristic value related to thermostability from the data of the amino acid sequence or the nucleotide sequence of the protein, and a recording medium having recorded the program thereon. More particularly, the invention relates to a program for allowing a computer to execute processing for judging the thermostability of a protein, which judges whether or not a test protein has thermostability by calculating an analytical value specific to the test protein by a principal component analysis based on the amino acid composition of the protein, and comparing the analytical value with an analytical value of a protein which is retained by a thermostable organism and corresponds to the test protein, and a computer readable recording medium having recorded the program thereon.
2. Background Art
Thermostable enzymes are widely used in the industrial world, research and development fields and the like as an enzyme that does not lose the enzymatic activity at a high temperature. Examples of the thermostable enzyme include, an enzyme used in an enzymatic reaction process for hydrolysis of a saccharide such as starch (see JP-T-10-506524 (the term “JP-T” as used herein means a published Japanese translation of a PCT patent application), and JP-A-2000-50870), an enzyme used in an enzymatic reaction in the disposal of food waste or in the production of a fertilizer from the food waste (see JP-A-2001-61474 and JP-A-2003-219864), an enzyme used in an enzymatic reaction in the production of a useful substance such as trehalose (see JP-A-08-336388 and JP-A-08-149980) and the like.
As described above, thermostable enzymes are very important in the industry. Recently, it has become important to develop a thermostable DNA polymerase to be used in the PCR method (see JP-B-04-67957), or in a replicative RNA-based amplification system (see JP-A-02-5864 and JP-A-02-500565), and a large number of thermostable DNA polymerases have been isolated mainly from thermophilic microorganisms. A DNA polymerase has become one of the important tools in genetic engineering techniques, and has become important as a tool not only for gene cloning or sequence determination, but also for detection or identification of a small amount of gene, namely, as an enzyme for gene amplification.
At present, thermostable DNA polymerases to be used mainly for these purposes are derived from the genus Thermus as Taq polymerase which is derived from T. aquaticus. The interest on the discovery of a novel polymerase with a more appropriate property and activity is growing, and as a DNA polymerase from other than the genus Thermus, for example, a method using a DNA polymerase from Anaerocellum thermophilum (see JP-T-2001-502169), a method using a DNA polymerase from a sulfur metabolism thermophilic archaebacterium Pyrococcus horikoshii (see JP-A-2000-41668) and the like have been reported.
In this way, the importance of thermostable enzymes is growing more and more, however, a search of such a thermostable enzyme often requires the steps of screening a bacterium producing a target enzyme from the natural world using thermophilic bacteria or thermostable bacteria as a target for screening, and confirming the thermostability of an enzyme produced by studying the culture conditions by performing a heat treatment one by one. Therefore, not only it required enormous time and effort, but also it depended on a coincidence in many cases. In addition, the subject of screening was limited to thermophilic bacteria, thermostable bacteria or mesophilic bacteria, and the thermophilic bacteria or thermostable bacteria was only limited species in light of numerous species of microorganisms, therefore the diversity of thermostable enzymes was limited.
Not only an accidental discovery is expected, but also the establishment of a systematic and saving method for searching a useful thermostable enzyme in industry was needed. Further, the development of a computer processable program, which is for conveniently executing the method was needed.